Old woman: grand pastry hoarder? (6)
I believe the answer is:
magpie
'hoarder?' is the definition.
(I know that magpie is a type of hoarder)
'old woman grand pastry' is the wordplay.
'old woman' becomes 'ma' (both can mean someone's mother).
'grand' becomes 'g' (G is short for grand as in a thousand).
'pastry' becomes 'pie' (pie is a kind of pastry).
'ma'+'g'+'pie'='MAGPIE'
(Other definitions for magpie that I've seen before include "winger" , "Bird - obsessive collector" , "Black and white bird, known as thieving" , "chatty bird" , "Half of 1D [GAME OR BIRD]" .)